Residual image display

ABSTRACT

In one of the present invention, a scanning control means and a generating means scan an image by part of light-emitting diodes among a plurality of light-emitting diodes, and generate two-dimensional residual image data enlarged from the image. A light-emission control means controls light emission of the plurality of light-emitting diodes by this enlarged two-dimensional residual image data.

TECHNICAL FIELD

The present invention relates to a residual image display device formaking its light-emitting diodes emit light.

BACKGROUND ART

Japanese Patent Application Laid-Open No. Hei 8-97969 (Hereinafterreferred to as Patent Document 1) discloses a scan type display devicehaving an image scanning function. This scan type display deviceincludes a light-emitting cell array and a light-receiving element. Thelight-emitting cell array is constituted with numerous light-emittingcells arranged linearly. Light radiated by the light-emitting cell,after being reflected on a surface of a shielding object, is madeincident on the light-receiving element. The scan type display deviceturns on a plurality of light-emitting cells one by one sequentially,and scans an image based on an output of the light-receiving element.This scan type display device reads out image data stored in a memorysequentially by a predetermined amount, and on/off drives thelight-emitting cell array according to the data. A user holds in a handand swings this scan type display device, to form a two-dimensionalimage by a residual image effect.

However, this conventional residual image display device disclosed inthe Patent Document 1 has various problems as follows.

A first problem is as follows. The conventional image display devicemakes the light-emitting cells emit light in sequence to perform scanprocessing of an image. Therefore, a size of the image to be scanned isrequired to be adjusted to a size of the array of the light-emittingcells. Namely, in order to make the conventional residual image displaydevice scan an image, it is necessary to make the image into the sizeadjusted to an array length of the plural light-emitting cells.

A second problem is as follows. The conventional image display devicemakes the light-emitting cells emit light to form a two-dimensionalresidual image. In order for the scanned image to be viewed as oneresidual image, light-emission of the light-emitting cells by thescanned data is required to be completed within a time being able to beviewed as one residual image. Therefore, in order for the scanned imageto be viewed as one residual image, it is necessary to make the size ofthe image to be scanned into equal to or smaller than a size that can beviewed as one residual image.

A third problem is as follows. The conventional residual image displaydevice is swung with the light-emitting cell array being faced to aperson to be shown. Therefore, a person who holds in hand and swings theresidual image display device cannot see the light-emitting cell array.The person who holds in hand and swings the residual image displaydevice can not check whether the scanned image is viewed as one residualimage or not.

A fourth problem is as follows. In the conventional residual imagedisplay device, the light-emitting cell in a displaying part turns on.The light-emitting cell in a non-displaying part turns off. Therefore,if the conventional residual image display device scans a line drawing,a letter, or the like, light-emitting cells that turn on are small innumber. Consequently, it is difficult for an observer to recognize whatkind of line drawing or letter is displayed. If the behind of the personwho holds in hand and waves the residual image display device is bright,the lights from the light-emitting cells are buried in the brightness ofthe background, and it is hard for the observer to recognize the image.

The present invention is made in view of the above problems and is tosolve one of the various problems in the conventional residual imagedisplay device using a plurality of light-emitting diodes, and therebyis to obtain a residual image display device easier to use than theconventional residual image display device.

DISCLOSURE OF THE INVENTION

A residual image display device according to the present inventionincludes: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of thehousing; a light-emitting means for making each of the light-emittingdiodes emit light individually; a light-receiving means for outputting asignal based on photoelectromotive force of each of part oflight-emitting diodes among the plurality of light-emitting diodes; ascanning control means for controlling the light-emitting means to makeeach of the light-emitting diodes emit light which is positionedneighboring the each of part of light-emitting diodes that thelight-receiving means outputs the signal based on the photoelectromotiveforce of, and for controlling the light-receiving means to output thesignal in the light-emitting state; a generating means for generatingtwo-dimensional residual image data of the plurality of light-emittingdiodes, based on the signals which are outputted from thelight-receiving means and which are based on the photoelectromotiveforce of the part of light-emitting diodes; a storing means for storingthe two-dimensional residual image data; and a light-emission controlmeans for controlling the light-emitting means to make the plurality oflight-emitting diodes emit light based on the two-dimensional residualimage data stored in the storing means, in accordance with swinging ofthe housing.

When this structure is adopted, under control of the scanning controlmeans, the light-receiving means outputs the signal based on thephotoelectromotive force of part of light-emitting diodes among theplural light-emitting diodes, and the generating means generatestwo-dimensional residual image data of the plural light-emitting diodesarranged along the longitudinal direction of the housing, based on thesignals which are outputted from the light-receiving means and which arebased on the photoelectromotive force of part of light-emitting diodes.The light-emission control means makes the plural light-emitting diodesemit light based on the two-dimensional residual image data. Therefore,the residual image display device according to the present invention canscan an image by part of light-emitting diodes among the plurallight-emitting diodes, and emit light by the plural light-emittingdiodes based on an enlarged image.

Another residual image display device according to the present inventionincludes: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of thehousing; a light-emitting means for making each of the plurality oflight-emitting diodes emit light individually; a light-receiving meansfor outputting a signal based on photoelectromotive force of each of theplurality of light-emitting diodes; a scanning control means forcotrolling the light-emitting means to make each of the light-emittingdiodes emit light which is positioned neighboring the each oflight-emitting diodes that the light-receiving means outputs the signalbased on the photoelectromotive force of, and for controlling thelight-receiving means to output the signal in the light-emitting state;a generating means for generating two-dimensional residual image data ofpart of light-emitting diodes among the plurality of light-emittingdiodes, based on the signals which are outputted from thelight-receiving means and which are based on the photoelectromotiveforce of the plurality of light-emitting diodes; a storing means forstoring the two-dimensional residual image data; and a light-emissioncontrol means for controlling the light-emitting means to make the partof light-emitting diodes among the plurality of light-emitting diodesemit light based on the two-dimensional residual image data stored inthe storing means, in accordance with swinging of the housing.

When this structure is adopted, under control of the scanning controlmeans, the light-receiving means outputs the signal based on thephotoelectromotive force of the plural light-emitting diodes, and thegenerating means generates two-dimensional residual image data of partof light-emitting diodes among the plural light-emitting diodes, basedon the signals which are outputted from the light-receiving means andwhich are based on the photoelectromotive force of the plurallight-emitting diodes. The light-emission control means makes part of oflight-emitting diodes emit light based on the two-dimensional residualimage data. Therefore, another residual image display device accordingto the present invention can scan an image by the plural light-emittingdiodes, and emit light by part of of light-emitting diodes based on areduced image.

A third residual image display device according to the present inventionincludes: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of thehousing; a light-emitting means for making the light-emitting diodesemit light individually; a light-receiving means for outputting a signalbased on photoelectromotive force of each of the light-emitting diodes;a scanning control means for controlling the light-emitting means tomake each of the light-emitting diodes emit light which is positionedneighboring the each of the light-emitting diodes that thelight-receiving means outputs the signal based on the photoelectromotiveforce of, and for controlling the light-receiving means to output thesignal in the light-emitting state; a generating means for generatingtwo-dimensional residual image data used for light-emission control ofthe light-emitting diodes, based on the signals which are outputted fromthe light-receiving means and which are based on the photoelectromotiveforce of the light-emitting diodes; a storing means for storing thetwo-dimensional residual image data; and a light-emission control meansfor controlling the light-emitting means to make the plurality oflight-emitting diodes emit light based on the two-dimensional residualimage data stored in the storing means, in accordance with swinging ofthe housing, wherein the light-emission control means controls lightemission so that a light-emission period of the light-emitting diodesbased on the two-dimensional residual image data is equal to or lessthan 1/30 second.

When this structure is adopted, the third residual image display deviceaccording to the present invention displays an image, regardless of asize of the scanned image, so that the light-emission period for theentire thereof becomes equal to or less than 1/30 second. Therefore, theentire of the scanned image is viewed as one residual image.

The above-described residual image display device according to eachinvention includes, in addition to the structure of each invention, adetecting means for detecting a change of a swing direction of thehousing, and, with using a timing when the detecting means detects thechange of the swing direction as a standard timing, after only a periodfrom a finishing timing of last light-emission of the light-emittingdiodes by the two-dimensional residual image data to the timing when thedetecting means detects the change of the swing direction is passed, thelight-emission control means starts light-emission of the light emittingdiodes by the two-dimensional residual image data.

When this structure is adopted, at a time that the residual imagedisplay device is repeatedly swung toward right and left, the residualimage formed in a period of each swinging is formed at a substantiallyfixed position in a space. Therefore, positions where the residualimages are formed are refrained from being displaced in every swinging,so that it becomes easy to view the image.

A fourth residual image display device according to the presentinvention includes: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of thehousing; a plurality of back face light-emitting diodes arranged alongthe longitudinal direction of the housing, in a back face of the housingthat is a reverse-side of the plurality of light-emitting diodes; alight-emitting means for making the light-emitting diodes and the backface light-emitting diodes emit light individually; a light-receivingmeans for outputting a signal based on photoelectromotive force of eachof the plurality of light-emitting diodes; a scanning control means forcontrolling the light-emitting means to make each of the light-emittingdiodes emit light which is positioned neighboring the each of thelight-emitting diodes that the light-receiving means outputs the signalbased on the photoelectromotive force of, and for controlling thelight-receiving means to output the signal in the light-emitting state;a generating means for generating two-dimensional residual image dataused for light-emission control of the light-emitting diodes, based onthe signals which are outputted from the light-receiving means and whichare based on the photoelectromotive force of the light-emitting diodes;a storing means for storing the two-dimensional residual image data; anda light-emission control means for controlling the light-emitting meansto make the plurality of light-emitting diodes and the back facelight-emitting diodes emit light based on the two-dimensional residualimage data stored in the storing means, in accordance with swinging ofthe housing.

When this structure is adopted, in a state that the plurallight-emitting diodes face an observer side, the plural back face lightemitting-diodes face the user. Consequently, by observing the residualimage by these plural back face light emitting-diodes, the user swingingthe residual image display device can check whether the image isdisplayed in a desired state or not by light-emission of the plurallight-emitting diodes.

A fifth residual image display device according to the present inventionincludes: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of thehousing; a plurality of different color light-emitting diodes emittinglight of a color different from that of the plurality of light-emittingdiodes, being arranged correspondingly to each of the plurality oflight-emitting diodes; a light-emitting means for making thelight-emitting diodes and the different color light-emitting diodes emitlight individually; a light-receiving means for outputting a signalbased on photoelectromotive force of each of the light-emitting diodes;a scanning control means for controlling the light-emitting means tomake each of the light-emitting diodes emit light which is positionedneighboring the each of the light-emitting diodes that thelight-receiving means outputs the signal based on the photoelectromotiveforce of, and for controlling the light-receiving means to output thesignal in the light-emitting state; a generating means for generatingtwo-dimensional residual image data used for light-emission control ofthe light-emitting diodes, based on the signals which are outputted fromthe light-receiving means and which are based on the photoelectromotiveforce of the light-emitting diodes; a storing means for storing thetwo-dimensional residual image data; and a light-emission control meansfor controlling the light-emitting means to make the plurality oflight-emitting diodes emit light based on the two-dimensional residualimage data stored in the storing means, and controlling thelight-emitting means to make the plurality of different colorlight-emitting diodes corresponding to each of the light-emitting meanswhich dose not emit light, in accordance with swinging of the housing.

When this structure is adopted, at a time that the light-emitting diodedoes not emit light, the different color light-emitting diodecorresponding thereto emits light. By this light emission of thedifferent color light-emitting diode, a background of the image isformed. Therefore, if a line drawing, a letter or the like is displayed,an observer can easily view what kind of image is being displayed by acontrast between a color of the light-emitting diode and a color of thedifferent color light-emitting diode. Consequently, even if a back ofthe user swinging the residual image display device is slightly bright,the observer standing face to face can view and recognize the imageaccurately based on the difference between the color of the backgroundand the color of the image.

In the fifth residual image display device according to the presentinvention, in addition to the above-described structure of theinvention, the scanning control means controlling, instead of to makeeach of the light-emitting diodes emit light which is positionedneighboring the each of the light-emitting diodes to perform scanning,to make each of the different color light-emitting diodes emit lightwhich is positioned neighboring the each of the light-emitting diodes toperform scanning, and for controlling to make the each of light-emittingdiodes receive reflected light of the light.

When this structure is adopted, at a time of image scanning, thelight-emitting diode is required to perform scanning only.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a transparent view showing a residual image display deviceaccording to a first embodiment of the present invention;

FIG. 2 is a circuit diagram showing an electric circuit which controls aplurality of light-emitting diodes and which is disposed inside theresidual image display device of FIG. 1;

FIG. 3 is a circuit diagram showing one set of a drive circuit and thelight-emitting diode in FIG. 1;

FIG. 4 is an explanatory diagram showing programs and data stored in amemory of a microcomputer in FIG. 2;

FIG. 5 is a flow chart showing control processing by a mode control unitof the first embodiment;

FIG. 6 is a flow chart showing control processing by a scanning controlunit of the first embodiment;

FIG. 7 is an explanatory diagram showing an example of cases thattwo-dimensional display data are scanned as residual image data by theresidual image display device of the first embodiment;

FIG. 8 is a chart showing two-dimensional residual image data written inthe memory when an image in FIG. 7 is scanned;

FIG. 9 is an explanatory diagram showing a case of scanning a numeralsmaller than a numeral in FIG. 7;

FIG. 10 is a chart showing two-dimensional residual image data writtenin the memory when an image in FIG. 9 is scanned;

FIG. 11 is a chart showing two-dimensional residual image data enlargedfrom the two-dimensional residual image data in FIG. 10;

FIG. 12 is a flow chart showing control processing by a light-emissioncontrol unit of the first embodiment;

FIG. 13 is a view showing an example of use to display a residual imageby using the residual image display device of the first embodiment;

FIG. 14 is an explanatory diagram of a modification example of theresidual image display device according to the first embodiment;

FIG. 15 is an explanatory diagram showing programs and data stored in amemory of a microcomputer of a second embodiment of the presentinvention;

FIG. 16 is a flow chart showing control processing by a scanning controlunit of the second embodiment;

FIG. 17 is a transparent view showing a residual image display deviceaccording to a third embodiment of the present invention;

FIG. 18 is a circuit diagram showing an electric circuit controlling aplurality of light-emitting diodes of a front face and a plurality ofback face light emitting-diodes of a back face, which is disposed insidethe residual image display device of FIG. 17;

FIG. 19 is an explanatory diagram showing programs and data stored in amemory of a microcomputer in FIG. 18;

FIG. 20 is a flow chart showing control processing by a light-emissioncontrol unit of the third embodiment;

FIG. 21 is a transparent view showing a residual image display deviceaccording to a fourth embodiment of the present invention;

FIG. 22 is a circuit diagram showing an electric circuit controlling aplurality of light-emitting diodes and a plurality of different colorlight-emitting diodes, which is disposed inside the residual imagedisplay device of FIG. 21

FIG. 23 is an explanatory diagram showing programs and data stored in amemory of a microcomputer in FIG. 22;

FIG. 24 is an explanatory diagram showing programs and data stored in amemory of a microcomputer of a fifth embodiment of the presentinvention; and

FIG. 25 is a flow chart showing control processing by a scanning controlunit of the fifth embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, residual image display devices according to embodiments ofthe present invention will be described with reference to the drawings.

Embodiment 1

FIG. 1 is a transparent view in which a residual image display deviceaccording to a first embodiment of the present invention is seen from aside.

The residual image display device includes a housing 1. The housing 1 isformed in a substantially cylindrical elongated bar shape. The housing 1is formed approximately 20 cm to 60 cm in length. At an end in alongitudinal direction of the housing 1, a grip section 2 for being heldin hand is disposed. The residual image display device is used in astate that this grip section 2 is held in hand and is swung side toside.

Inside the grip section 2, a later-described battery 11 is disposed.Because of weight of the battery 11, the center of gravity of theresidual image display device is located near the grip section 2.Therefore, when the grip section 2 is held in hand and swung, theresidual image display device gives a feeling of a light swing weight toa user.

Hereinafter, a section from the other end in the longitudinal directionof the housing 1 to the grip section 2 is called a tip section 3 of theresidual image display device. In this tip section 3, along thelongitudinal direction of the residual image display device, a pluralityof light-emitting diodes 4 are arranged in a row. A side of the housing1 on which these plural light-emitting diodes 4 are arranged is a frontface side (lower side in FIG. 1) of the respective light-emitting diodes4, and is a front face side of the residual image display device.

The light-emitting diodes 4 emit light, by anodes having higher electricpotentials than cathodes so that electric currents flow inside. Thehigher the electric potentials of the anodes become than the electricpotentials of the cathodes, the larger quantity of electric currentsflow in the light-emitting diodes 4 so that the light-emitting diodes 4emit strong light. In the first embodiment, light-emitting diodes thatemit red light are used as the light-emitting diodes 4.

Photoelectric conversion characteristic of the light-emitting diode 4has reversibility. Namely, when the light-emitting diode 4 innon-emitting state receives incident light, the electric currentcorresponding to light intensity thereof flows from the anode to thecathode. As a result, a subtle voltage is excited in the light-emittingdiode 4. The voltage excited in the light-emitting diodes 4 becomeslarger as the light intensity of the incident light increases.

As the light-emitting diodes 4, other than the light-emitting diodeswhich emit red light, there are ones which emit green light, blue light,and white light and so on. It is possible to arrange the light-emittingdiodes that emit light of any one color among these, instead of the onesthat emit red light, in the tip section 3 of the residual image displaydevice. Also, it is possible to combine the light-emitting diodes thatemit different colors and arrange them in the tip section 3 of theresidual image display device.

Between the light-emitting diodes 4 and the grip section 2, a startbutton 5 is disposed. On a back face side of the tip section 3 of thehousing 1, there are disposed a power supply switch 6, a mode settingswitch 7, and a scanning magnification setting switch 8.

Between the start button 5 and the grip section 2, a circular ringmember 9 is disposed. The circular ring member 9 is formed in a donutshape having a circular outer shape and a circular inner shape. Thehousing 1 is inserted into the circular inner shape. The circular ringmember 9 is rotatable around the housing 1. An outer circumference ofthe circular ring member 9 is slightly larger than the outer shape ofthe housing 1.

At a tip of the housing 1, a disk member 10 is rotatably disposed. Anouter circumference of the disk member 10 is substantially the same asthe outer circumference of the circular ring member 9. Namely, the outercircumference of the circular ring member 9 is slightly larger than theouter shape of the housing 1.

Since these circular ring member 9 and disk member 10 are provided, in astate that the residual image display device is put on a desk and thelike, the circular ring member 9 and the disk member 10 come in contactwith a surface of the desk. When the residual image display device ismoved on the desk, the circular ring member 9 and the disk member 10rotate. The housing 1 smoothly moves above the surface of the desk,keeping a fixed distance (space H shown in FIG. 1) between the surfaceof the desk.

The outer circumference of the circular ring member 9 and the outercircumference of the disk member 10 can preferably be made anti-slip bygiving projections and depressions as to be like a pear surface or byapplying an adhesive tape. When the residual image display device ismoved on the surface of the desk, slippage between the surface of thedesk and the circular ring member 9 as well as the disk member 10becomes eliminated or decreases. As a result, rotation quanta of thecircular ring member 9 and the disk member 10 become completely equal toor substantially the same as a distance which the residual image displaydevice moves on the surface of the desk.

FIG. 2 is a circuit diagram showing an electric circuit that controlsthe plural light-emitting diodes 4. This electric circuit is disposedinside the residual image display device of FIG. 1.

In the electric circuit disposed inside the residual image displaydevice, the power supply switch 6 is connected between a plus electrodeof the battery 11 and a power supply line 21. A minus electrode of thebattery 11 is connected to a ground line 22. In practice, the battery 11is accommodated in an unshown battery box for replacement convenience,and this battery box is connected to the power supply switch 6 and theground line 22. It may be carried out that the power supply switch 6 isconnected between the minus electrode of the battery 11 and the groundline 22.

The electric circuit includes a microcomputer 23. The microcomputer 23includes a central processing unit (CPU) 24, a memory 25 as a storagemeans, and a timer 26.

To the microcomputer 23, a mercury relay 27 as a detection means, thestart button 5, the mode setting switch 7, the scanning magnificationsetting switch 8, and a rotary encoder 28 are connected.

The mercury relay 27 includes a cell for containing mercury, a firstterminal which projects in the cell, a second terminal which projects inthe cell at a position facing the first terminal, and a third terminalwhich projects in the cell between the first terminal and the secondterminal. The mercury relay 27 is disposed at the tip of the housing 1.The mercury relay 27 is disposed in a position where a direction fromthe first terminal to the second terminal is along the swing directionof the residual image display device. Accordingly, for example, when theresidual image display device is swung from right to left as viewed froma front, conduction between the first terminal and the third terminal isconducted by the mercury, the second terminal and the third terminal isconducted by the mercury when the residual image display device is swungfrom left to right as viewed from the front. The microcomputer 23 judgesthe swing direction of the residual image display device by detectingwhich of the first terminal or the second terminal the third terminal isconducted to.

Instead of this mercury relay 27, a speed sensor, a swing directionsensor or the like can be used. The swing direction sensor accommodates,for example, a ball in a cylindrical cavity, with light-emittingelements and light-receiving elements being disposed at respective endsof the cylindrical cavity. If the sensor is disposed in a position wherean axial direction of the cylindrical cavity is along the swingdirection of the residual image display device, when the residual imagedisplay device is swung from one side to the other side, light from thelight-emitting element is blocked by the ball having moved to the oneside and a light-receiving signal is not obtained from thelight-receiving element of the one side. On the other hand, when theresidual image display device is swung from the other side to the oneside, the ball having moved to the other side blocks light from thelight-emitting element and a light-receiving signal is not obtained fromthe light-receiving element of the other side. The microcomputer 23judges the swing direction of the residual image display device bydetecting which light reception of these two light-receiving elements isblocked.

Both ends of the start button 5 are connected to the microcomputer 23.The microcomputer 23 detects whether conduction between two terminalsconnected to the start button 5 is conducted or not, to detect whetherthe start button 5 is pressed or not.

One end of the mode setting switch 7 is connected to the microcomputer23. The other end of the mode setting switch 7 is connected to the powersupply line 21. Between the one end of the mode setting switch 7 and theground line 22, a resistance element 29 is connected. When the modesetting switch 7 becomes in ON state, a voltage of the power supply line21, i.e. a high-level is inputted to the microcomputer 23. When the modesetting switch 7 becomes in OFF state, a voltage of the ground line 22,i.e. a low level is inputted to the microcomputer 23. The microcomputer23 judges two modes by judging the level of the voltage inputted fromthis mode setting switch 7. In the first embodiment, the microcomputer23 judges a case of the high level as a scanning mode and judges a caseof the low level as a light-emitting mode.

One end of the scanning magnification setting switch 8 is connected tothe microcomputer 23. The other end of the scanning magnificationsetting switch 8 is connected to the power supply line 21. Additionally,between the one end of the scanning magnification setting switch 8 andthe ground line 22, a resistance element 30 is connected. When thescanning magnification setting switch 8 becomes in ON state, a highlevel is inputted to the microcomputer 23. When the scanningmagnification switch 8 becomes in OFF state, a low level is inputted tothe microcomputer 23. The microcomputer 23 judges two modes by judgingthe level of the voltage inputted from the scanning magnificationsetting switch 8. In the first embodiment, the microcomputer 23 judges acase of the high level as an enlargement mode and judges a case of thelow level as a normal mode.

The rotary encoder 28 reads a rotation quantity of the disk member 10.Every time the rotation quantity of the disk member 10 becomes apredetermined rotation angle, a pulse is outputted. This pulse isinputted to the microcomputer 23. The microcomputer 23 judges therotation quantity of the disk member 10 by counting a number of theinputted pulses.

To the microcomputer 23, a multiplexer 31 is connected. To themultiplexer 31, a plurality of drive circuits 32 are connected. Therespective drive circuits 32 are connected to the respectivelight-emitting diodes 4. The multiplexer 31 and the drive circuits 32function as a light-emitting means and a light-receiving means.

FIG. 3 is a circuit diagram showing one set of the drive circuit 32 andthe light-emitting diode 4 in FIG. 1.

The drive circuit 32 includes a first voltage-dividing resistanceelement 41 connected to the power supply line 21, and a secondvoltage-dividing resistance element 42 connected between the firstvoltage-dividing resistance element 41 and the ground line 22. Thecathode of the light-emitting diode 4 is connected between the firstvoltage-dividing resistance element 41 and the second voltage-dividingresistance element 42. To the anode of the light-emitting diode 4, acollector of a PNP transistor 43 is connected. An emitter of the PNPtransistor 43 is connected to the power supply line 21. Between a baseof the PNP transistor 43 and the ground line 22, two resistance elements44 and 45 are connected in series. When the base of the PNP transistor43 is controlled to the low level and the PNP transistor 43 becomes inON state, a current flows from the PNP transistor 43 to thelight-emitting diode 4, so that the light-emitting diode 4 emits redlight.

To the anode of the light-emitting diode 4, a gate of a FET (FieldEffect Transistor) 46 is further connected. Between a source of the FET46 and the power supply line 21, a load resistance element 47 isconnected. Between a drain of the FET 46 and the ground line 22, aresistance element 48 is connected. To the gate of the FET 46, an addedvoltage is applied, which is obtained by adding a voltage of the secondvoltage-dividing resistance element 42 and a voltage generated in thelight-emitting diode 4. In the FET 46, a current flows, which iscorresponding to a potential difference between this added voltage andthe voltage of the ground line 22. This current generates a voltage inthe load resistance element 47. When the voltage generated in thelight-emitting diode 4 changes according to a change of light intensityincident on the light-emitting diode 4 in non-emitting control state, avoltage of the load resistance element 47 changes in accordance withthis change.

The multiplexer 31 includes two switch arrays, as shown in FIG. 2.

One switch array of the two switch arrays is constituted with aplurality of switches 51. Respective one terminals of the pluralswitches 51 are connected to a common terminal. This common terminal isconnected to an AD port of the microcomputer 23. The AD port convertsanalog data to digital data. The respective switches 51 of the oneswitch array are connected between the load resistance elements 47 andthe sources of the FET 46 of the respective drive circuits 32. Theplural switches 51 are opened/closed by a light-reception switchingsignal from the microcomputer 23. The switch 51 designated by thelight-reception switching signal is closed. The voltage of the loadresistance element 47 of the drive circuit 32 connected to the closedswitch 51 is inputted to the AD port of the microcomputer 23. It shouldbe noted that in the first embodiment the plural switches 51 of the oneswitch array are opened when the light-reception switching signal is notinputted.

The other switch array of the two switch arrays is constituted with aplurality of switches 52. Respective one ends of the plural switches 52are connected to a common terminal. This common terminal is connected tothe power supply line 21. The respective switches 52 of the other switcharray are connected between the two resistance elements 44 and 45 of therespective drive circuits 32. The plural switches 52 are opened/closedby a light-emission switching signal from the microcomputer 23. Theswitch 52 designated by the light-reception switching signal is opened.The PNP transistor 43 of the drive circuit 32 connected to the openedswitch 52 becomes in ON state so that the light emitting diode 4 emitslight. It should be noted that in the first embodiment the pluralswitches 52 of the other switch array are closed when thelight-reception switching signal is not inputted.

FIG. 4 is an explanatory diagram showing programs and data stored in thememory 25 of the microcomputer 23 in FIG. 2.

In the memory 25, a mode control program 61, a scanning control program62, and a light-emission control program 63 are stored. In the memory25, two-dimensional residual image data 64, minimum valid column data65, maximum valid column data 66, and a switching time 67 are stored.

Next, an operation of the residual image display device structured asabove will be described.

When the power supply switch 6 switches from OFF state to ON state, avoltage of the battery 11 is provided to the power supply line 21. Sincethe plural switches 52 of the other switch array are closed, the plurallight-emitting diodes 4 do not emit light.

Electric power provided by the power supply line 21 activates themicrocomputer 23. When the microcomputer 23 is activated, the centralprocessing unit 24, after completing various internal settings, executesthe mode control program 61. Accordingly, a mode control unit isrealized.

FIG. 5 is a flow chart showing control processing by the mode controlunit.

The mode control unit judges a level of a voltage inputted from the modesetting switch 7 (ST1). If the voltage level is a high level, the modecontrol unit judges it as the scanning mode, and makes the centralprocessing unit 24 execute the scanning control program 62 (ST2). If thevoltage level is a low level, the mode control unit judges it as thelight-emitting mode, and makes the central processing unit 24 executethe light-emission control program 63 (ST3).

By the central processing unit 24 executing the scanning control program62, a scanning control unit which functions as a scanning control meansand a generating means is realized. FIG. 6 is a flow chart showingcontrol processing by the scanning control unit.

The scanning control unit erases data written in the two-dimensionalresidual image data 64, the switching time 67, the minimum valid columndata 65, and the maximum valid column data 66 (ST11). Thereafter, thescanning control unit becomes in a standby state waiting for a pressingoperation of the start button 5 (ST12).

FIG. 7 is an explanatory diagram showing an example of cases thattwo-dimensional display data 70 are scanned as the residual image data64 by the residual image display device. In the example of FIG. 7, thedisplay data 70 is a character data 72 as a numeral “2”, which isprinted in black vertically on a white sheet 71, the vertical length ofwhich is longer than the width of it. This sheet 71 and the residualimage display device are placed on the surface of the desk, for example.The sheet 71 is placed in a way that a surface on which the numeral “2”is printed faces up. The residual image display device is placed on aleft side in a horizontal direction of the sheet 71.

For example, a user set the scanning magnification setting switch 8 inOFF state, and then presses the start button 5. Then, the user moves theresidual image display device from a left end to a right end of thesheet 71, keeping the front of the residual image display device facingdown, i.e., keeping the plural light-emitting diodes 4 facing thesurface of the desk. When the residual image display device has moved toa right side of the sheet 71, the start button 5 is released.

By the start button 5 being pressed, the scanning control unit startsscan processing. The scanning control unit performs scan processing ofthe residual light image data on a column-by-column basis (ST13).

In the scan processing of the residual light image data on acolumn-by-column basis, the scanning control unit first outputs thelight-reception switching signal for closing the switch 51 which isconnected via the drive circuit 32 to a top light-emitting diode 4 inFIG. 2, as well as outputs the light-emission switching signal forclosing the switch 52 which is connected via the drive circuit 32 to asecond light-emitting diode 4 from the top in FIG. 2. Accordingly, thesecond light-emitting diode 4 from the top in FIG. 2 emits light. Thelight emitted from the second light-emitting diode 4 is reflected on thesheet 71, and received by the top light-emitting diode 4 in FIG. 2. Tothe microcomputer 23, a voltage of a level corresponding to a receivedlight intensity of the top light-emitting diode 4 in FIG. 2 is inputted.

A received light intensity of the light-emitting diode 4 issubstantially proportionate to a reflected light intensity reflected onthe sheet 71. The whiter a color of the sheet 71 is the more thereflected light intensity is, while the blacker the color of the sheet71 is the less the reflected light intensity is. The level of thevoltage inputted to the microcomputer 23 becomes lower as the color ofthe sheet 71 is whiter, and becomes higher as the color of the sheet 71is blacker. The microcomputer 23, comparing this level of the voltagewith a predetermined threshold level, judges the color of the sheet 71to be black if a voltage higher than the threshold level is inputted,and writes “1” into the memory 25 as the two-dimensional residual imagedata 64. The microcomputer 23 judges the color of the sheet 71 to bewhite if a voltage lower than the threshold level is inputted, andwrites “0” into the memory 25 as the two-dimensional residual image data64. Incidentally, correspondence between the judged color and the valuewritten into the memory 25 can be reversed. The predetermined thresholdlevel can have been stored in the memory 25, for example.

After the value based on the received light intensity of the toplight-emitting diode 4 in FIG. 2 is written into the memory 25, thescanning control unit outputs the light-reception switching signal forclosing the switch 51 which is connected via the drive circuit 32 to thesecond light-emitting diode 4 from the top in FIG. 2, as well as outputsthe light-emission switching signal for closing the switch 52 which isconnected via the drive circuit 32 to the third light-emitting diode 4from the top in FIG. 2. The scanning control unit, comparing the levelof the voltage corresponding to the received light intensity of thesecond light-emitting diode 4 from the top in FIG. 2 with thepredetermined threshold level, writes the value corresponding to thejudged color into the memory 25 as the two-dimensional residual imagedata 64.

The scanning control unit performs the light-reception processing by therespective light-emitting diodes 4 as to all the light-emitting diodes4. Accordingly, the same number of values as a number of thelight-emitting diodes 4 is written into the memory 25 as the residuallight image data for one column. Incidentally, there is nolight-emitting diode 4 below the bottommost light-emitting diode 4 inFIG. 2. Therefore, when the light is to be received by the bottommostlight-emitting diode 4 in FIG. 2, the second light-emitting diode 4 fromthe bottom in FIG. 2, for example, can be made emit light.

When scanning of the residual light image data for one column as aboveis completed, the scanning control unit checks whether the start button5 is kept pressed or not (ST14), and if the start button 5 is keptpressed, the scanning control unit judges amoving-distance-between-columns of the residual image display device,based on a number of pulses inputted from the rotary encoder 28 (ST15).When the moving-distance-between-columns of the residual image displaydevice becomes equal to or more than a predetermined moving distance,the above described scan processing of the residual light image data forone column is performed (ST13). Accordingly, into the memory 25,residual light image data of two columns in total are written.Incidentally, the predetermined moving distance can have been stored inthe memory 25, for example.

The scanning control unit repeats the scan processing of the residuallight image data for one column (ST13 to ST15) in the everypredetermined moving-distance-between-columns, until the start button 5become unpressed. When, in FIG. 7, the start button 5 is released at atime that the residual image display device has moved to the right sideof the sheet 71, the two-dimensional residual image data 64 as shown inFIG. 8 are written into the memory 25. In an example shown in FIG. 8,the two-dimensional residual image data 64 are constituted with theresidual image data for nine columns from a first column to a ninthcolumn.

When the start button 5 becomes unpressed, the scanning control unitreads a voltage level inputted from the scanning magnification settingswitch 8, and judges whether enlargement or not (ST16). On thisoccasion, since the scanning magnification setting switch 8 is in OFFstate, the scanning control unit judges it as the normal mode based onthe voltage of the low level. The scanning control unit writes theminimum valid column data 65, the maximum valid column data 66, and theswitching time 67 into the memory 25 based on the two-dimensionalresidual image data 64 stored in the memory 25 (ST17, ST18, and ST19).

The minimum valid column data 65 are generated by procedures statedbelow, for example. The scanning control unit judges whether “1” isincluded in the column of the two-dimensional residual image data 64 ornot, from the first column in order. The scanning control unit extractsa column number of the first column in the column data of which “1” isincluded for the first time. The scanning control unit writes thisextracted column number into the memory 25 as the minimum valid columndata 65. In the two-dimensional residual image data 64 in FIG. 8, “2”equivalent to the second column is written into the memory 25 as theminimum valid column data 65.

The maximum valid column data 66 are generated by procedures statedbelow, for example. The scanning control unit judges whether “1” isincluded in the column of the two-dimensional residual image data 64 ornot, from the last column in order. The scanning control unit extracts acolumn number of the first column in the column data of which “1” isincluded for the first time. The scanning control unit writes thisextracted column number into the memory 25 as the maximum valid columndata 66. In the two-dimensional residual image data 64 in FIG. 8, “8”equivalent to the eighth column is written into the memory 25 as themaximum valid column data 66.

The switching time 67 is generated by procedures stated below, forexample. The scanning control unit calculates a number of columns fromthe minimum valid column data 65 to the maximum valid column data 66.The scanning control unit next divides a display time of 33.3 ms (≈ 1/30second) by the number of the columns. The scanning control unit writes aquotient thereof into the memory 25 as the switching time 67. In thetwo-dimensional residual image data 64 in FIG. 8, the minimum validcolumn data 65 is the second column and the maximum valid column data 66is the eighth column. The number of the columns is 7 columns. Therefore,the scanning control unit writes 4.7 ms (≈33.3 ms÷7), for example, intothe memory 25 as the switching time 67.

Next, as shown in FIG. 9, a case of scanning numerical character data72A that is smaller in size than the numeral in FIG. 7 will bedescribed. Also in this case, the scanning control unit performsprocessing based on the flow chart shown in FIG. 6. When a display data70A being a small-sized image is scanned, the scanning magnificationsetting switch 8 is set to be in ON state in advance.

Thereafter, when the start button 5 is pressed (ST12), the scanningcontrol unit starts scan processing. The scanning control unit repeatsscan processing of the residual light image data on a column-by-columnbasis (ST13 to ST15) in every predeterminedmoving-distance-between-columns, until the start button 5 becomeunpressed.

It should be noted that, as shown in FIG. 9, only half of the plurallight-emitting diodes 4 positioned nearer to the tip of the housing 1are used for scanning based on setting of the scanning magnificationsetting switch 8. Incidentally, the plural light-emitting diodes 4 usedfor this scanning can be only the half ones nearer to the grip section 2of the housing 1, can be only the ones in a central part of the housing1, or can be the ones which are arranged sequentially to each other inan arrangement of the plural light-emitting diodes 4.

In FIG. 9, if the start button 5 is released at a time that the residualimage display device has moved to a right side of the sheet 71A,two-dimensional residual image data 64 are written into the memory 25 asshown in FIG. 10. The two-dimensional residual image data 64 shown inFIG. 10 are constituted with residual image data of five columns from afirst column to a fifth column.

When the start button 5 becomes unpressed, the scanning control unitreads a voltage level inputted from the scanning magnification settingswitch 8, and judges whether enlargement or not (ST16). On thisoccasion, since the scanning magnification setting switch 8 is in ONstate, the scanning control unit judges it as an enlargement mode basedon the voltage of the high level. The scanning control unit performsenlargement processing of the scanned image (ST20). Namely, for example,the scanning control unit performs processing to double the lengths ofthe scanned two-dimensional residual image data 64. This means that theimage becomes 4 times in size.

The processing to double the image length is realized by followingprocessing, for example. The scanning control unit reads a last columnnumber of the two-dimensional residual image data 64. Here, the lastcolumn number is represented by “m” (“m” is a natural number). Thescanning control unit writes data of an m-th column of the readtwo-dimensional residual image data 64 into a (2m−1)-th column and a2m-th column. Next, the scanning control unit writes data of a (m−1)-thcolumn of the read two-dimensional residual image data 64 into a(2m−3)-th column (=2 (m−1)−1) and a (2m−2)-th column (=2 (m−1)). Suchmigration processing of the column data is performed up to a firstcolumn. Accordingly, the image by the read two-dimensional residualimage data 64 is doubled in a column direction.

The scanning control unit, next, reads a last row number of thetwo-dimensional residual image data 64. Here, the last row number isrepresented by “n” (“n” is a natural number). The scanning control unitwrites data of an n-th row of the read two-dimensional residual imagedata 64 into a (2n−1)-th row and a 2n-th row. Next, the scanning controlunit writes data of a (n−1)-th row of the read two-dimensional residualimage data 64 into a (2n−3)-th row (=2 (n−1)−1) and a (2n−2)-th row (=2(n−1)). Such migration processing of the row data is performed up to afirst row. Accordingly, the image by the read two-dimensional residualimage data 64 is doubled in a row direction.

By the above processing, the two-dimensional residual image data 64stored in the memory 25 become double in the image length (4 times inthe image size) of the read two-dimensional residual image data 64. Inthis way, based on the residual image data 64 in FIG. 10, newtwo-dimensional residual image data 64 shown in FIG. 11 are generated.Incidentally, the two-dimensional residual image data 64 shown in FIG.11 has substantially the same image size as the two-dimensional residualimage data 64 in FIG. 8.

A magnification can be other magnifications such as a triplemagnification and the like. Also, the magnification can be fixed atdouble, triple, or the like, and can be chosen among the fixedmagnification by the user. In the above description, the processing ofdoubling in the row direction after doubling in the column direction isperformed, but the same two-dimensional residual image data 64 can beobtained by performing the processing of doubling in the columndirection after first doubling in the row direction. In the abovedescription, enlarged two-dimensional residual image data 64 isgenerated only by the processing of simple migration of data, but it ispossible to obtain two-dimensional residual image data 64 which hasgenerated with after migration process such as outline processing,interpolation processing and so on.

When the enlargement processing of the image size of the readtwo-dimensional residual image data 64 is completed, the scanningcontrol unit writes the minimum valid column data 65, the maximum validcolumn data 66, and the switching time 67 into the memory 25, based onthe enlarged two-dimensional residual image data 64 stored in the memory25 (ST17, ST18, and ST19). In the case of the two-dimensional residualimage data 64 in FIG. 11, the minimum valid column data 65 is the thirdcolumn, the maximum valid column data 66 is the eighth column, and theswitching time 67 is 5.5 ms (≈33.3 ms÷6).

After the scanning control unit processing above process, there arestored two-dimensional residual image data 64 in the memory 25, theminimum valid column data 65, the maximum valid column data 66, and theswitching time 67. When the voltage level inputted from the mode settingswitch 7 is the low level, the mode control unit, judging it as thelight-emitting mode, makes the central processing unit 24 execute thelight-emission control program 63. By the central processing unit 24executing the light-emission control program 63, a light-emissioncontrol unit which functions as a light-emission control means isrealized.

FIG. 12 is a flow chart showing control processing by the light-emissioncontrol unit. The light-emission control unit first becomes a standbystate waiting for a pressing operation of the start button 5 (ST31).

FIG. 13 is a view showing an example of use to display a residual imageby using the residual image display device. The user, after pressing thestart button 5, holds the grip section 2 of the residual image displaydevice in hand. The user starts waving the residual image display devicewith the front of the residual image display device facing in a frontdirection of himself. Here, the user starts to swing from a right-handdirection to a left-hand direction of himself (in an arrow direction Ain FIG. 13). The user swings the residual image display device back andforth within a predetermined swing angle range by reversing the swingdirection alternately, in such a way that after swinging in thedirection A, swinging in an opposite direction (in an arrow direction Bin FIG. 13), and further in the direction A. It should be noted that inthe following description there has been stored in the memory 25 thetwo-dimensional residual image data 64 shown in FIG. 8.

The light-emission control unit starts light-emission processing by thestart button 5 being pressed. The light-emission control unit firstjudges the swing direction of the residual image display device based ona continuity state of the mercury relay 27 (ST32). If the swingdirection is from the right-hand direction to the left-hand direction ofthe user himself, the light-emission control unit performs forwardlight-emission processing. If the swing direction is from the left-handdirection to the right-hand direction of the user himself (in the arrowdirection B in FIG. 13), the light-emission control unit performsreverse light-emission processing.

The forward light-emission processing is, for example, followingprocessing. The light-emission control unit reads the minimum validcolumn data 65 stored in the memory 25 and assigns the column number ofthe minimum valid column data 65 to a variable “x” (ST33). Thelight-emission control unit reads data of an x-th column of thetwo-dimensional residual image data 64 and outputs a light-emissioncontrol signal for making the light-emitting diode 4 corresponding to arow having a data value “1” emit light. In the two-dimensional residualimage data 64 in FIG. 8, the second row is designated as the minimumvalid column data 65. Accordingly, a fourth light-emitting diode 4 fromthe top, a fifth light-emitting diode 4 from the top, and a twelfthlight-emitting diode 4 from the top in FIG. 2 emit light (ST34).

The light-emission control unit judges, based on a value of the timer26, whether a time T1 from a start of the above light-emission of thesecond column becomes equal to or more than the switching time 67 storedin the memory 25 or not. In the two-dimensional residual image data 64in FIG. 8, whether the T1 becomes equal to or more than 4.7 ms or not isjudged (ST35). When a light-emission time period of the x-th columnbecomes equal to or more than 4.7 ms, the light-emission control unitincrements the value of the variable x by one (ST36), and judges whetherthis incremented value of the variable x exceeds the column number ofthe maximum valid column data 66 or not (ST37). The value of x at thistiming is “3”, being smaller than the column number (“8”) of the maximumvalid column data 66. Therefore, the light-emission control unit readsdata of a third column of the two-dimensional residual image data 64,and outputs a light-emission control signal for making thelight-emitting diode 4 corresponding to a row having a data value “1”emit light (ST34).

The light-emission control unit repeats the increment processing of thevariable x and the switch processing of the light-emission controlsignal every time the time T1 becomes equal to or more than theswitching time 67. When the value of the incremented variable x exceedsthe column number of the maximum valid column data 66, thelight-emission control unit ends read-out processing of thetwo-dimensional residual image data 64 (ST34 to ST37). In FIG. 8, at atime that the value of the variable x becomes “9”, the read-outprocessing ends. Accordingly, during 32.9 ms (4.7 ms×7) when the valueof the variable x varies from “2” to “9”, the data from the second rowto the eighth row of the two-dimensional residual image data 64 are readout, and based on these data light emission of the plural light-emittingdiodes 4 are controlled. Consequently, by one swing in the arrowdirection A in FIG. 13, as shown in FIG. 13, a person on a front faceside of the user sees the numeral “2” as the residual image.

When the read-out processing of the two-dimensional residual image data64 ends, the light-emission control unit resets the timer 26 (ST38).Thereafter, the light-emission control unit becomes in a stand by statewaiting for detection of reversing (ST39). The light-emission controlunit monitors the conduction state of the mercury relay 27. When theswing direction of the residual image display device is detected to bein reverse based on the conduction state of the mercury relay 27, i.e.the swing direction of the residual image display device changes fromthe left-hand direction to the right-hand direction of the user himself(the arrow direction B in FIG. 13), the light-emission control unitstores a value of the timer 26 at that timing into the memory 25 (ST40)and immediately resets the timer 26 (ST41). The value of the timer 26stored in the memory 25 is a time T2 from the timer reset timing (ST38)to the detection timing of reverse. Next, the light-emission controlunit monitors the value of the timer 26. When the value of the timer 26becomes equal to or more than the value of the timer 26 stored in thememory 25, i.e. the time T2 (ST42), the light-emission control unitstarts reverse light-emission processing.

The reverse light-emission processing is, for example, followingprocessing. The light-emission control unit reads the maximum validcolumn data 66 stored in the memory 25 and assigns the column number ofthe maximum valid column data 66 to a variable “x” (ST43). Thelight-emission control unit reads data of an x-th column of thetwo-dimensional residual image data 64 and outputs a light-emissioncontrol signal for making the light-emitting diode 4 corresponding to arow having a data value “1” emit light. In the two-dimensional residualimage data 64 in FIG. 8, the eighth row is designated as the maximumvalid column data 66. Accordingly, the fourth light-emitting diode 4from the top, the fifth light-emitting diode 4 from the top, the sixthlight-emitting diode 4 from the top, and the twelfth light-emittingdiodes 4 from the top in FIG. 2 emit light (ST44).

The light-emission control unit judges, based on the value of the timer26, whether a time T3 from a start of the above light-emission of theeighth column becomes equal to or more than the switching time 67 storedin the memory 25 or not. In the two-dimensional residual image data 64in FIG. 8, whether the T3 becomes equal to or more than 4.7 ms or not isjudged (ST45). When a light-emission time period of the x-th columnbecomes equal to or more than 4.7 ms, the light-emission control unitdecrements the value of the variable x by one (ST46), and judges whetherthis decremented value of the variable x is smaller than the columnnumber of the minimum valid column data 65 or not (ST47). A value of xat this timing is “7”, being larger than the column number “2” of theminimum valid column data 65. Therefore, the light-emission control unitreads data of a seventh column of the two-dimensional residual imagedata 64, and outputs a light-emission control signal for making thelight-emitting diode 4 corresponding to a row having a data value “1”emit light (ST44).

The light-emission control unit repeats the decrement processing of thevariable x and the switch processing of the light-emission controlsignal every time the time T3 becomes equal to or more than theswitching time 67. When the value of the decremented variable x becomessmaller than the column number of the minimum valid column data 65, thelight-emission control unit ends read-out processing of thetwo-dimensional residual image data 64 (ST44 to ST47). In FIG. 8, at atime that the value of the variable x becomes “1”, the read-outprocessing ends. Accordingly, during 32.9 ms (4.7 ms×7) when the valueof the variable x varies from “8” to “1”, the data from the eighth rowto the second row of the two-dimensional residual image data 64 are readout, and based on these data the plural light-emitting diodes 4 arelight-emission controlled. Consequently, by one swing in the arrowdirection B, as shown in FIG. 13, the person on the front face side ofthe user sees the numeral “2” as the residual image.

When the read-out processing of the two-dimensional residual image data64 ends, the light-emission control unit resets the timer 26 (ST48).Thereafter, the light-emission control unit becomes in a standby statewaiting for detection of reversing (ST49). The light-emission controlunit monitors the conduction state of the mercury relay 27. When theswing direction of the residual image display device is detected to bereversed based on the conduction state of the mercury relay 27, i.e. theswing direction of the residual image display device changes from theright-hand direction to the left-hand direction of the user himself, thelight-emission control unit stores a value of the timer 26 at thattiming into the memory 25 (ST50) and immediately resets the timer 26(ST51). The value of the timer 26 stored in the memory 25 at this timeis a time T4 from the timer reset timing (ST48) to detection timing ofreverse. Next, the light-emission control unit monitors the value of thetimer 26. When the value of the timer 26 becomes equal to or more thanthe time T4 being the value of the timer 26 stored in the memory 25(ST52), the light-emission control unit performs the forwardlight-emission processing.

As described above, in the residual image display device of the firstembodiment, by being swung from the right-hand direction to theleft-hand direction of the user himself (the arrow direction A in FIG.13), the light-emission control unit performs the forward light-emissionprocessing (ST33 to ST42), as well as by being swung from the left-handdirection to the right-hand direction of the user himself (the arrowdirection B in FIG. 13), the light-emission control unit performs thereverse light-emission processing (ST43 to ST52). The residual imagedisplay device repeats the forward light-emission processing and thereverse light-emission processing in accordance with the swing directionof the residual image display device. Therefore, by the user continuingswinging the residual image display device within substantially the sameswing ranges as shown in FIG. 13, the light-emission control unitperforms the forward light-emission processing and the reverselight-emission processing alternately, so that the residual images basedon the two-dimensional residual image data 64 are repeatedly displayed.

This residual image display device of the first embodiment scans theimage by part of light-emitting diodes 4 among the plural light-emittingdiodes 4, and generates the two-dimensional residual image data 64 thatis enlarged from the scanned image. The residual image display devicecontrols light emission of the plural light-emitting diodes 4 by theenlarged two-dimensional residual image data 64. Therefore, the residualimage display device can scan the image by part of light-emitting diodes4 among the plural light-emitting diodes 4 and enlarge and display theimage by the plural light-emitting diodes 4.

This residual image display device of the first embodiment displays theimage part, i.e. an entire light-emitting part, in or less than 1/30second, regardless of the size of the scanned image. Therefore, anentire of the scanned image is viewed as one residual image. Moreover,the residual image display device controls timing of a start of the nextlight-emission, by utilizing the time from ending of the image displayto reversing. Therefore, even if the swing range of the repeated backand forth swinging of the residual image display device varies in everyswinging, the residual image formed by every swinging is formed at asubstantially fixed position in a space. Consequently, displacements ofthe residual images in every swinging are restrained, so that it becomeseasy to view the image.

In this residual image display device of the first embodiment, in a casethat the two-dimensional residual image data 64 shown in FIG. 11 arestored in the memory 25, the light-emission control unit reads out thedata from the third row to the eighth row of the two-dimensionalresidual image data 64 during 33 ms (≈5.5.ms×6). Consequently, theresidual image display device can show the person on the front face sideof the user the numeral “2” as the residual image, similarly to thetwo-dimensional residual image data 64 shown in FIG. 8.

In this residual image display device of the first embodiment, in thescan processing of the residual light image data for one column (ST13),the scanning control unit controls the light-emitting diodes 4 one byone sequentially from the top to be in a light-receiving state, andcontrols the light-emitting diode 4 neighboring the light-emitting diode4 in the light-receiving state to be in a light-emitting state. Inaddition to this, it is possible to control in a way, for example, asshown in FIG. 14, that the plural light-emitting diodes 4 are dividedinto an even ordinal number group and an odd ordinal number group, thelight-emitting diodes 4 in the even ordinal number group being made intothe light-receiving state while the light-emitting diodes 4 in the oddordinal number group being made into the light-emitting state, and thelight-emitting diodes 4 in the odd ordinal number group being made intothe light-receiving state while the light-emitting diodes 4 in the evenordinal number group being made into the light-emitting state.Accordingly, the light-reception processing of the plural light-emittingdiodes 4 can be performed simultaneously in groups, so that the scanningtime of the residual light image for one column is shortened. In anexample of FIG. 14, first, the light-emitting diodes 4 in the evenordinal number group are made into the light-receiving state, and next,the light-emitting diodes 4 in the odd ordinal number group are madeinto the light-receiving state. The black painted square corresponds to“1” and the white square corresponds to “0”.

Embodiment 2

A hardware structure of a residual image display device according to asecond embodiment is the same as that of the residual image displaydevice according to the first embodiment shown in FIG. 1 to FIG. 3. Indescribing the hardware structure of the residual image display deviceaccording to the second embodiment, the same reference numerals andsymbols as those in the hardware structure of the residual image displaydevice according to the first embodiment shown in FIG. 1 to FIG. 3 areused and detailed description thereof will be restrained.

A microcomputer 23 in the second embodiment judges a scanningmagnification setting switch 8 being in ON state as a reduction mode,based on a level of a voltage inputted from this scanning magnificationsetting switch 8. The microcomputer 23 judges the scanning magnificationsetting switch 8 being in OFF state as a normal mode, based on a levelof a voltage inputted from the scanning magnification setting switch 8.

FIG. 15 is an explanatory diagram showing programs and data stored in amemory 25 of the microcomputer 23 of the second embodiment of thepresent invention. In the memory 25, a mode control program 61, ascanning control program 81, and a light-emission control program 63 arestored. In the memory 25, two-dimensional residual image data 64,minimum valid column data 65, maximum valid column data 66, and aswitching time 67 are stored.

By a central processing unit 24 of the microcomputer 23 executing themode control program 61, a mode control unit is realized. By the centralprocessing unit 24 of the microcomputer 23 executing the scanningcontrol program 81, a scanning control unit which functions as ascanning control means and a generating means is realized. By thecentral processing unit 24 of the microcomputer 23 executing thelight-emission control program 63, a light-emission control unit isrealized. The mode control unit and the light-emission control unitaccording to the second embodiment execute the same control flows asthose having the same names according to the first embodiment.Therefore, in the second embodiment, the same reference numerals andsymbols are used to designate the programs having the same names in thefirst embodiment, and detailed description thereof will be restrained.

FIG. 16 is a flow chart showing control processing by the scanningcontrol unit according to the second embodiment.

The scanning control unit erases respective data of the two-dimensionalresidual image data 64, the minimum valid column data 65, the maximumvalid column data 66, and the switching time 67, which are written inthe memory 25 (ST11). Thereafter, the scanning control unit becomes in astandby state waiting for a pressing operation of the start button 5(ST12).

By the start button 5 being pressed, the scanning control unit startsscan processing. The scanning control unit performs scan processing ofthe residual light image data on a column-by-column basis (ST13 toST15). When the start button 5 becomes unpressed, the scanning controlunit reads a voltage level inputted from the scanning magnificationsetting switch 8. On this occasion, since the scanning magnificationsetting switch 8 is in ON state, the scanning control unit judges it asthe reduction mode based on the voltage of the high level (ST61). Thescanning control unit performs the reduction processing of an image(ST62). Namely, for example, the scanning control unit performsprocessing to half the lengths of the scanned two-dimensional residualimage data 64. This means that the image becomes quarter in size.

The processing to reduce the image size in half is realized by followingprocessing, for example. Here, a case that the two-dimensional residualimage data 64 shown in FIG. 11 are scanned will be described as anexample. The two-dimensional residual image data 64 shown in FIG. 11 aredata of 12 rows×10 columns. Hereinafter, when the respective data of thetwo-dimensional residual image data 64 are individually designated, theyare stated as (n, m) data (in FIG. 11, “n” is each integer from 1 to 12,and “m” is each integer from 1 to 10). For example, statement as (2, 3)data means data of a second row and a third column.

The scanning control unit assigns “1” to a variable “x” and a variable“y”, reads (x, y) data, (x, y+1) data, (x+1, y) data, and (x+1, y+1)data, then calculates an average value thereof. If the average value isequal to or more than 0.5, “1” is written into the (x, y) data. If theaverage value is smaller than 0.5, “0 (zero)” is written into the (x, y)data. More specifically, the scanning control unit first reads (1, 1)data, (1, 2) data, (2, 1) data, and (2, 2) data, and calculates theaverage value thereof. In FIG. 11, since each of the four read data is“0”, the average value becomes “0” and “0” is written into the (1, 1)data.

Next, the scanning control unit adds “2” to the variable x and repeatssimilar average value processing. The scanning control unit repeats thisuntil the value of the valuable x becomes equal to a number oflight-emitting diodes 4 or to a value obtained by adding “1” to thenumber of the light-emitting diodes 4. Accordingly, a first column ofthe residual image data shown in FIG. 10 is stored in the memory 25.

Also, the scanning control unit adds “2” to the variable y and repeatsthis generation processing for one column. Accordingly, a second columnof the residual image data shown in FIG. 10 is stored in the memory 25.The scanning control unit repeats this until the value of the variable ybecomes equal to a column number of a last column or to a value obtainedby adding “1” to the column number of the last column of the readtwo-dimensional residual image data 64. Accordingly, all of the residualdata shown in FIG. 10 are stored in the memory 25.

By the above processing, the two-dimensional residual image data 64stored in the memory 25 becomes half in length of the readtwo-dimensional residual image data 64. Accordingly, the scanningcontrol unit can obtain data having the same size as in a case thatimage data of the similar size to the image of the size shown in FIG. 9are read, based on an image of the size shown in FIG. 7. Namely, basedon the residual image data 64 of the size shown in FIG. 11, there aregenerated the residual image data 64 of the size shown in FIG. 10. Inthe reduction processing, “0” is written into each part of the memorywhere the update data is not over written. Accordingly, all the residualimage data before reduction are erased from the memory 25. A reductionratio can be other reduction ratios such as reduction to one third andthe like. The reduction ratio can be chosen among the fixed reductionratios by the user.

The scanning control unit generates minimum valid column data 65,maximum valid column data 66, and switching time 67 of this reducedtwo-dimensional residual image data 64, and makes the memory 25 storethem (ST17, ST18, and ST19). A control flow of the scanning control unitin a case of a normal mode is the same as that of the normal mode in thefirst embodiment, and description will be restrained.

The light-emission control unit controls light-emission of the plurallight-emitting diodes 4 based on the two-dimensional residual image data64 reduced as above, every time the residual image display device isswung from side to side. Accordingly, the residual image display devicerepeatedly displays residual images based on the reduced two-dimensionalresidual image data 64.

As described above, the residual image display device of the secondembodiment scans the image by the plural light-emitting diodes 4 andgenerates the two-dimensional residual image data 64 reduced from thescanned image. The residual image display device controls light-emissionof the plural light-emitting diodes 4 in part, with the reducedtwo-dimensional residual image data 64. Therefore, the residual imagedisplay device can scan the image by the plural light-emitting diodes 4,and reduce and display that image by part of light-emitting diodes 4 ofthe plural light-emitting diodes 4. Which of the plural light-emittingdiodes 4 are used for emission can be freely chosen.

Embodiment 3

FIG. 17 is a transparent view in which a residual image display deviceaccording to a third embodiment of the present invention is seen from aside.

On a back face of a tip section 3 of the residual image display deviceof the third embodiment, a plurality of back face light emitting-diodes91 are arranged in a row. In the residual image display device, sincestructures other than the plural light-emitting diodes 4 of back facehave the same functions as in the residual image display device of thefirst embodiment, the same reference numerals and symbols as in thefirst embodiment are used and detailed description thereof will berestrained.

FIG. 18 is a circuit diagram showing an electric circuit controlling aplurality of light-emitting diodes 4 of the front face and the pluralback face light emitting-diodes 91 of the back face, which is disposedinside the residual image display device of FIG. 17.

To a microcomputer 23, a second multiplexer 92 is connected. The secondmultiplexer 92 includes one switch array. The switch array isconstituted with a plurality of switches 93. One ends of the respectiveplural switches 93 are connected to a common terminal. This commonterminal is connected to a power supply line 21. The respective switches93 are connected to anodes of the respective back face light-emittingdiodes 91. Cathodes of the plural back face light-emitting diodes 91 areconnected to a ground line 22.

The plural switches 93 are opened/closed by a back face light-emissionswitching signal from the microcomputer 23. The switch 93 designated bythe back face light-emission switching signal is closed. The back facelight emitting-diode 91 connected to the closed switch 93 emits light.The plural switches 93 of the second multiplexer 92 in the thirdembodiment are opened, when the back face light-emission switchingsignal is not inputted.

Since components of the electric circuit other than the above have thesame functions as in the residual image display device of the firstembodiment, the same reference numerals and symbols as those in thefirst embodiment are used and detailed description thereof will berestrained.

FIG. 19 is an explanatory diagram showing programs and data stored inthe memory 25 of the microcomputer 23 in FIG. 18.

In the memory 25, a mode control program 61, a scanning control program62, and a light-emission control program 94 are stored. In the memory25, two-dimensional residual image data 64, minimum valid column data65, maximum valid column data 66, and a switching time 67 are stored.

By a central processing unit 24 of the microcomputer 23 executing themode control program 61, a mode control unit is realized. By the centralprocessing unit 24 of the microcomputer 23 executing the scanningcontrol program 62, a scanning control unit is realized. By the centralprocessing unit 24 of the microcomputer 23 executing the light-emissioncontrol program 94, a light-emission control unit which functions as alight-emission control means is realized. The mode control unit and thescanning control unit according to the third embodiment execute the samecontrol flows as those having the same names according to the firstembodiment. In the programs and the control flows according to the thirdembodiment, the same reference numerals and symbols are used to theprograms and steps having the same names as those in the firstembodiment, and detailed description thereof will be restrained. Thescanning control unit can execute the same control flow as that of thesame name in the second embodiment.

FIG. 20 is a flow chart showing control processing by the light-emissioncontrol unit. The light-emission control unit first becomes in a standbystate waiting for a pressing operation of a start button 5 (ST31).

By the start button 5 being pressed, the light-emission control unitstarts light-emission processing. The light-emission control unit firstjudges a swing direction of the residual image display device based on aconduction state of a mercury relay 27 (ST32). If the swing direction isfrom a right-hand direction to a left-hand direction of a user himself(in an arrow direction A in FIG. 13), the light-emission control unitperforms forward light-emission processing. If the swing direction isfrom the left-hand direction to the right-hand direction of the userhimself (in an arrow direction B in FIG. 13), the light-emission controlunit performs reverse light-emission processing.

In the forward light-emission processing, the light-emission controlunit assigns a column number of the minimum valid column data 65 as aninitial value to a variable x, as well as assigns a column number of themaximum valid column data 66 as an initial value to a variable y (ST71).Thereafter, the light-emission control unit reads data of an x-th columnof two-dimensional residual image data 64, and outputs a light-emissioncontrol signal for making the light-emitting diode 4 corresponding to arow having a data value “1” emit light. Additionally, the light-emissioncontrol unit reads data of a y-th column of the two dimensional residualimage data 64, and outputs a back face light-emission control signal formaking the back face light emitting-diode 91 corresponding to a rowhaving a data value “1” emit light (ST72).

The light-emission control unit judges, based on a value of a timer 26,whether a time T1 from a start of the light-emission of the above x-thcolumn becomes equal to or more than a switching time 67 stored in thememory 25 or not (ST35). The light-emission control unit increments thevalue of the variable x by one as well as decrements the value of thevariable y by one (ST73). If this incremented value of the variable xexceeds the column number of the maximum valid column data 66 (ST37),the light-emission control unit ends read-out processing of thetwo-dimensional residual image data 64 (ST72, ST35, and ST73). If thevalue of the variable x does not exceed the column number of the maximumvalid column data 66, the light-emission control unit continues thelight-emission control by the variable x and the variable y (ST72, ST35,and ST73).

The residual image display device, based on the residual image displaydevice being swung from the right-hand direction to the left-handdirection of the user himself, reads out data in a range from the columnnumber of the minimum valid column data 65 to the column number of themaximum valid column data 66 of the two-dimensional residual image data64 in a sequential order on a column-by-column basis, during a time thatthe value of the variable x varies from the column number of the minimumvalid column number data 65 to more than the column number of themaximum valid column data 66, and based on these data, controlslight-emission of the plural light-emitting diodes 4. Consequently, whenthe residual image display device is swung in the arrow direction A, asshown in FIG. 13, a person on a front face side of the user sees anumeral “2” as a residual image.

During a time that the value of the variable x varies from the columnnumber of the minimum valid column number data 65 to more than thecolumn number of the maximum valid column data 66, the value of thevariable y varies from the column number of the maximum valid columndata 66 to less than the column number of the minimum valid column data65. The residual image display device reads out data in the range fromthe column number of the maximum valid column data 66 to the columnnumber of the minimum valid column data 65 of the two-dimensionalresidual image data 64 in a sequential order on a column-by-columnbasis, and base on these data, controls light-emission of the pluralback face light emitting-diodes 91. Consequently, when the residualimage display device is swung in the arrow direction B, people on a backface side the user including the person swinging the residual imagedisplay device see the numeral “2” as the residual image. Morespecifically, on the back face side, the numeral “2” is displayedsequentially from right to left, and as a result “2” is displayed as theresidual image.

When the read-out processing of the two-dimensional residual image data64 ends, the light-emission control unit resets the timer 26 (ST38),detecting reversing based on a conduction state of a mercury relay 27(ST39), and stores a time T2 being a value of a detected timing at thetimer 26 into the memory 25 (ST40). The light-emission control unitresets the timer 26 (ST41), and when the value of the timer 26 becomesequal to or more than the time T2 being the value of the timer 26 storedin the memory 25, the light-emission control unit ends the forwardlight-emission processing (ST42), starting the reverse light-emissionprocessing.

The reverse light-emission processing is, for example, followingprocessing. In the reverse light-emission processing, the light-emissioncontrol unit assigns the column number of the maximum valid column data66 as an initial value to the variable x, as well as assigns the columnnumber of the minimum valid column data 65 as an initial value to thevariable y (ST74). Thereafter, the light-emission control unit reads thedata of the x-th column of the two-dimensional residual image data 64,and outputs a light-emission control signal for making thelight-emitting diode 4 corresponding to a row having a data value “1”emit light. The light-emission control unit reads the data of the y-thcolumn of the two-dimensional residual image data 64, and outputs a backface light-emission control signal for making the back face lightemitting-diode 91 corresponding to a row having a data value “1” emitlight (ST75).

The light-emission control unit judges, based on a value of the timer26, whether a time T3 from a start of the light-emission of the abovex-th column becomes equal to or more than a switching time 67 stored inthe memory 25 or not (ST45). The light-emission control unit decrementsthe value of the variable x by one as well as increments the value ofthe variable y by one (ST76). When the value of the decremented variablex becomes less than the column number of the minimum valid column data65 (ST47), the light-emission control unit ends the read-out processingof the two-dimensional residual image data 64 (ST75, ST45, and ST76). Ifthe decremented value of the variable x is not less than the columnnumber of the minimum valid column data 65, the light-emission controlunit repeats the light-emission control by the variable x and thevariable y (ST75, ST45, and ST76).

The residual image display device, based on the residual image displaydevice being swung from the left-hand direction to the right-handdirection of the user himself, reads out data in a range from the columnnumber of the maximum valid column data 66 to the column number of theminimum valid column data 65 of the two-dimensional residual image data64 in a sequential order on a column-by-column basis, during a time thatthe value of the variable x varies from the column number of the maximumvalid column data 66 to less than the column number of the minimum validcolumn data 65, and based on these data, controls light emission of theplural light-emitting diodes 4. Consequently, as shown in FIG. 13,during a time that the residual image display device is swung in thearrow direction B, the person on the front face side of the user seesthe numeral “2” as the residual image.

During the time that the value of the variable x varies from the columnnumber of the maximum valid column data 66 to less than the columnnumber of the minimum valid column data 65, the value of the variable yvaries from the column number of the minimum valid column data 65 tomore than the column number of the maximum valid column data 66. Theresidual image display device reads out data in the range from thecolumn number of the minimum valid column data 65 to the column numberof the maximum valid column data 66 of the two-dimensional residualimage data 64 in the sequential order on a column-by-column basis, andbased on these data, controls light emission of the plural back facelight emitting-diodes 91. Consequently, people on the back face side ofthe user including the user can see the numeral “2” as the residualimage.

When the read-out processing of the two-dimensional residual image data64 (ST75, ST45, and ST76) ends, the light-emission control unit resetsthe timer 26 (ST48), detects reversing based on the conduction state ofthe mercury relay 27 (ST49), and stores a time T4 being a value of adetected timing at the timer 26 into the memory 25 (ST50). Thelight-emission control unit resets the timer 26 (ST51), and when thevalue of the timer 26 becomes equal to or more than the time T4 beingthe value of the timer 26 stored in the memory 25, ends the reverselight-emission processing (ST52), starting the forward light-emissionprocessing.

As described above, by the residual image display device of the thirdembodiment being swung from the right-hand direction to the left handdirection of the user himself, the light-emission control unit performsthe forward light-emission processing, and by the residual image displaydevice of the third embodiment being swung from the left-hand directionto the right-hand direction of the user himself, the light-emissioncontrol unit performs the reverse light-emission processing. In theresidual image display device, by the user continuing swinging theresidual image display device in substantially the same swing ranges asshown in FIG. 13, the light-emission control unit performs the forwardlight-emission processing and the reverse light-emission processingalternately, and repeatedly displays, on the front face side and theback face side, the residual images based on the two-dimensionalresidual image data 64.

Even when the residual image display device is swung in a state that theplural light-emitting diodes 4 face an observer side, the user swingingthe residual image display device can check what image is beingdisplayed by observing the residual image by these plural back facelight emitting-diodes 91, since the plural back face lightemitting-diodes 91 face himself.

Embodiment 4

FIG. 21 is a perspective view showing a residual image display deviceaccording to a fourth embodiment of the present invention in a statethat a housing 1 of a tip section 3 thereof is taken off.

On a front face of the tip section 3 of the residual image displaydevice of the fourth embodiment, there are arranged a plurality ofdifferent color light-emitting diodes 101 in the other row, separatelyfrom a plurality of light-emitting diodes 4. The respective differentcolor light-emitting diodes 101 are arranged to be one-to-onecorrespondent to the respective light-emitting diodes 4. The differentcolor light-emitting diodes 101 emit blue light.

Between the tip section 3 and a grip section 2 of the residual imagedisplay device, an unshown changeover switch 103 is disposed.

Since structures other than the above have the same functions as thosein the residual image display device of the first embodiment, the samereference numerals and symbols as in the first embodiment are used anddetailed description thereof will be restrained.

FIG. 22 is a circuit diagram showing an electric circuit controlling theplural light-emitting diodes 4 and the plural different colorlight-emitting diodes 101, which is disposed inside the residual imagedisplay device of FIG. 21.

To a plurality of switches 52 of the other switch array, buffers 102 areconnected respectively. The respective buffers 102 are connected toanodes of the respective different color light-emitting diodes 101.Cathodes of the plural different color light-emitting diodes 101 areconnected commonly to a changeover switch 103. The changeover switch 103is connected to a ground line 22. Since structures other than the abovehave the same functions as those in the residual image display device ofthe first embodiment, the same reference numerals and symbols as thosein the first embodiment are used and detailed description thereof willbe restrained.

FIG. 23 is an explanatory diagram showing programs and data stored in amemory 25 of a microcomputer 23 in FIG. 22.

In the memory 25, a mode control program 61, a scanning control program62, and a light-emission control program 104 are stored. In the memory25, two-dimensional residual image data 64, minimum valid column data65, maximum valid column data 66, and a switching time 67 are stored.

By a central processing unit 24 of the microcomputer 23 executing themode control program 61, a mode control unit is realized. By the centralprocessing unit 24 of the microcomputer 23 executing the scanningcontrol program 62, a scanning control unit is realized. By the centralprocessing unit 24 of the microcomputer 23 executing the light-emissioncontrol program 104, a light-emission control unit which functions as alight-emission control means is realized. The mode control unit, thescanning control unit, and the light-emission control unit according tothe second embodiment execute the same control flows as those of thesame names according to the first embodiment. In the programs andcontrol flows according to the fourth embodiment, the same referencenumerals and symbols are used to designate the programs and the steps ofthe same names as those in the first embodiment, and detaileddescriptions thereof will be restrained.

The scanning control unit outputs a light-emission switching signal formaking the plural light-emitting diodes 4 emit light, in accordance witha swing direction of the residual image display device, based ontwo-dimensional image data stored in the memory 25. At this time, theswitch 52 of the other switch array, which is designated by thelight-emission switching signal, is opened. The light-emitting diode 4connected to the opened switch 52 via a drive circuit 32 emits light.

When the light-emitting diode 4 emits light as just described, a lowlevel is inputted to the buffer 102 to which the opened switch 52 isconnected. This buffer 102 outputs the low level. Therefore, even if thechangeover switch 103 is closed, the different color light-emittingdiode 101 does not light.

On the other hand, when the switch 52 of the other switch array isclosed, the light-emitting diode 4 connected to the closed switch 52 viathe drive circuit 32 does not light. When the light-emitting diode 4does not light as just described, to the buffer 102 to which the closedswitch 52 is connected, a high level is inputted. This buffer 102outputs the high level. Therefore, if the changeover switch 103 isclosed, the different color light-emitting diode 101 lights.

When the residual image display device is swung in a state that thechangeover switch 103 is closed, the plural light-emitting diodes 4 arecontrolled their turning on and off states based on “1” of thetwo-dimensional image data, and the plural different colorlight-emitting diodes 101 are controlled their turning on and off statesbased on “0” of the two-dimensional image data. Therefore, there is abackground image as a residual image is formed by the plural differentcolor light-emitting diodes 101 on the periphery of the image formed asa residual image by the plural light-emitting diodes 4.

As stated above, in the residual image display device of the fourthembodiment, if the light-emitting diode 4 does not emit light, thedifferent color light-emitting diode 101 corresponding thereto emitslight. During a time that light emission of the light-emitting diode 4is controlled, the background of the image is formed by the differentcolor light-emitting diode 101. Therefore, even if in a state where aline drawing, a letter, or the like is displayed, an observer can easilyview what kind of image is being displayed based on a contrast between alight color of the light-emitting diode 4 and a light color of thedifferent color light-emitting diode 101. Even if a backside of a userswinging the residual image display device is slightly bright, theobserver can view the image accurately based on a difference between thecolor of the background and the color of the image.

When the light-emitting diode 4 and the different color light-emittingdiode 101 are widely apart each other, their light-emissions control arerequired to be based on their lightning timing/position differences, butwhen a distance between the light-emitting diode 4 and the differentcolor light-emitting diode 101 is not so apart each other, theirlight-emissions are controlled as them existing in a same row.

Embodiment 5

A hardware structure of a residual image display device according to afifth embodiment is the same as the structure of the residual imagedisplay device according to the fourth embodiment. To the hardwarestructure of the residual image display device, the same referencenumerals and symbols as in the hardware structure in the residual imagedisplay device according to the fourth embodiment are used and detaileddescription thereof will be restrained.

FIG. 24 is an explanatory diagram showing programs and data stored in amemory 25 of a microcomputer 23 of the fifth embodiment of the presentinvention. In the memory 25, a mode control program 61, a scanningcontrol program 111, and a light-emission control program 104 arestored. In the memory 25, two-dimensional residual image data 64,minimum valid column data 65, maximum valid column data 66, and aswitching time 67 are stored.

By the a central processing unit 24 of the microcomputer 23 executingthe mode control program 61, a mode control unit is realized. By thecentral processing unit 24 of the microcomputer 23 executing thescanning control program 111, a scanning control unit which functions asa scanning control means and a generating means is realized. By thecentral processing unit 24 of the microcomputer 23 executing thelight-emission control program 104, a light-emission control unit isrealized. The mode control unit and the light-emission control unitaccording to the fifth embodiment execute the same control flows asthose having the same names according to the fourth embodiment.Therefore, in the programs and the control flows according to the fifthembodiment, the same reference numerals and symbols are used todesignate the programs and the steps having the same names as those inthe fourth embodiment, and detailed descriptions thereof will berestrained.

FIG. 25 is a flow chart showing control processing by the scanningcontrol unit. Incidentally, when the scan processing is executed, achangeover switch 103 is closed. The scanning control unit erasesrespective data written in the two-dimensional residual image data 64,the minimum valid column data 65, the maximum valid column data 66, andthe switching time 67, which are stored in the memory 25 (ST11).Thereafter, the scanning control unit becomes in a standby state waitingfor a pressing operation of a start button 5 (ST 12).

By the start button 5 being pressed, the scanning control unit startsscan processing. The scanning control unit performs scan processing ofthe residual light image data on a column-by-column basis (ST81). Morespecifically, for example, the scanning control unit first outputs alight-reception switching signal for closing a switch 51 which isconnected via a drive circuit 32 to a top light-emitting diode 4 in FIG.22, as well as outputs a light-emission switching signal for closing aswitch 52 which is connected via a drive circuit 32 to a first differentcolor light-emitting diode 101 from a top in FIG. 22. Accordingly, thefirst different color light-emitting diode 101 from the top in FIG. 22emits light. Then, the light is reflected on a sheet 71, and received bythe top light-emitting diode 4 in FIG. 22. To the microcomputer 23, avoltage of a level corresponding to a received light intensity of thetop light-emitting diode 4 in FIG. 22 is inputted.

The microcomputer 23, comparing the level of the voltage with apredetermined threshold level, judges a color of a image to be blackwhen a voltage higher than the threshold level is inputted, and writes“1” into the memory 25 as the two-dimensional residual image data 64.The microcomputer 23 judges the color of the image to be white when avoltage lower than the threshold level is inputted, and writes “0” intothe memory 25 as the two-dimensional residual image data 64.Incidentally, correspondence between the judged color and the valuewritten in the memory 25 can be reversed. The predetermined thresholdlevel can have been stored in the memory 25, for example.

When writing of the value based on the received light intensity of thetop light-emitting diode 4 in FIG. 22 ends, the scanning control unitoutputs the light-reception switching signal for closing the switch 51which is connected via the drive circuit 32 to a second light-emittingdiode 4 from the top in FIG. 22, as well as outputs the light-emissionswitching signal for closing the switch 52 which is connected via thedrive circuit 32 to the second different color light-emitting diode 101from the top in FIG. 22. The scanning control unit, comparing a level ofa voltage corresponding to a received light intensity of the secondlight-emitting diode 4 from the top in FIG. 22 and the predeterminedthreshold level, writes a value corresponding to a judged color into thememory 25 as the two-dimensional residual image data 64.

The scanning control unit performs the light reception processing by therespective light-emitting diodes 4 as to all the light-emitting diodes4. Accordingly, the same number of values as a number of thelight-emitting diodes 4 is written into the memory 25 as the residuallight image data for one column.

When scanning of the residual light image data for one column (ST81) asabove is completed, the scanning control unit checks that the startbutton 5 is kept pressed (ST14). If the start button 5 is kept pressed,the scanning control unit judges a moving-distance-between-columns ofthe residual image display device, based on a number of pulses inputtedfrom a rotary encoder 28 (ST15). When themoving-distance-between-columns of the residual image display devicebecomes equal to or more than a predetermined moving distance, thescanning control unit performs the above-described scan processing ofthe residual light image data for one column (ST81). Accordingly,residual light image data for two columns are written into the memory25. The predetermined moving distance can have been stored in the memory25 in advance, for example.

When the start button 5 become unpressed, based on a voltage levelinputted from a scanning magnification setting switch 8, the scanningcontrol unit executes an enlargement mode as necessary (ST16).Thereafter, based on the two-dimensional residual image data 64 storedin the memory 25, the scanning control unit generates minimum validcolumn data 65, maximum valid column data 66, and a switching time 67,and make the memory 25 store them (ST17, ST18, and ST19).

When writing and the like of the residual light image data for twocolumns into the memory 25 ends, the scanning control unit becomes astate where display of the image is possible.

The light-emission control unit controls light-emission of the plurallight-emitting diodes 4 based on the two-dimensional residual image data64 stored in the memory 25 and displays the residual image every timeswung from side to side. If a changeover switch 103 is closed, thedifferent color light-emitting diode 101 emits light at timing when thelight-emitting diode 4 is turned off. There is a background image as aresidual image is formed by the plural different color light-emittingdiodes 101 on the periphery of the image formed as a residual image bythe plural light-emitting diodes 4.

In the meantime, in the fifth embodiment, the different colorlight-emitting diode 101 that emits blue light and the light-emittingdiode 4 that emits red light are combinedly used, and the light-emittingdiode 4 that emits red light receives blue emitted light to scan theimage.

The light-emitting diode 4 basically has a structure in which a P-typesemiconductor and an N-type semiconductor are combined. The P-typesemiconductor is connected to an anode, while the N-type semiconductoris connected to a cathode. When an energy gap between the P-typesemiconductor and the N-type semiconductor is denoted by Eg, if a lighthaving a wavelength shorter than a wavelength λ shown by a followingequation 1 is made incident on a joint portion of the P-typesemiconductor and the N-type semiconductor, photoelectromotive forceoccurs at the light-emitting diode.λ=1240/Eg (nm)  equation 1

In the light-emitting diode 4 that emits red light, this wavelength λ isapproximately 660 nm. In other words, the light-emitting diode 4 thatemits red light generates the photoelectromotive force by the lighthaving the wavelength shorter than approximately 660 nm incidentthereon. The light-emitting diode that emits blue light emits light of awavelength between 400 nm and 600 nm. Therefore, the light-emittingdiode 4 that emits red light generates the photoelectromotive force bythe light of the different color light-emitting diode 101 that emitsblue light. On the other hand, the light-emitting diode that emits bluelight does not generate the photoelecromotive force by the light of thelight-emitting diode 4 that emits red light.

By using, as the different color light-emitting diode 101, thelight-emitting diode which emits light of the wavelength shorter thanthat of an emitted light color of the light-emitting diode 4 used as alight-receiving element, it is possible to make the light-emitting diode4 generate an electromotive force by the light of the different colorlight-emitting diode 101 so as to scan the image. Among the emittedlight colors (in a range of visible light) of the light-emitting diodesare, for example, one which emits red light of approximately 660 nm, onewhich emits orange light of approximately 620 nm, one which emits yellowlight of approximately 570 nm, one which emits yellow green light ofapproximately 565 nm, one which emits blue light of approximately 490nm, one which emits white light, and so on. The one that emits whitelight can be one that purely emits white light or one combined of onesthat emit three colors of red, green, and blue light.

Therefore, if the light emitting diode which emits red light is used asthe light-emitting diode 4, for example, scanning of the image ispossible with either one which emits any other color being used as thedifferent color light-emitting diode 101. On the other hand, if thelight-emitting diode that emits blue light is used as the light-emittingdiode 4, scanning of the image is possible only in a combination withthe one that emits white light by combination of three colors of red,green, and blue, as the different color light-emitting diode 101.

As stated above, the residual image display device of the fifthembodiment makes the different color light-emitting diode 101 emit lightand makes the light-emitting diode 4 receive reflected light of thatlight, to scan the image. Therefore, at a time of scanning the image,the light-emitting diode 4 needs to perform only scanning.

The respective embodiments described above are preferable embodiments ofthe present invention, and various kinds of changes and modification arepossible without departing from the gist of the present invention.

In the respective embodiments described above, there are describedexamples in which plural light-emitting diodes 4 are arranged in a rowfrom the end of the tip section 3 toward the grip section 2, but it ispossible that the light-emitting diodes are circularly arranged in acircumferential direction to be a plane vertical to an axis direction ofthe residual image display device and the residual image display deviceis operated in a way to be swung from side to side in the axisdirection. In addition to this, it is also possible that the residualimage display device is formed into a balloon shape with thelight-emitting diodes being arranged along a ruling direction thereof orwith the light-emitting diodes being arranged along a direction of anauxiliary line.

In the respective embodiments described above, the residual imagedisplay device has a bar-shaped housing. In addition to this, thestructure of the present invention can also be used, for example, for aflicker which is used by a police officer or a traffic control personfor road repair by holding it in hand, for a mars light which isinstalled on a police car, a fire engine, or the like, or which isprovided for security, for a revolving light, or for a signal light orso forth. By making these light emitting devices scan and displayarbitrary images or letters as image data, as compared with a case ofsimply blinking or lighting on, it is possible to display a message andthe like for respective purposes so that more correct andeasy-to-understand instruction or display can be readily performed, andat the same time a modification thereof can be easily made.

INDUSTRIAL AVAILABILITY

A residual image display device of the present invention can be appliedto a residual image display device having a plurality of light-emittingdiodes.

1-7. (canceled)
 8. A residual image display device, comprising: asubstantially bar-shaped housing; a plurality of light-emitting diodesarranged along a longitudinal direction of said housing; alight-emitting means for making each of said light-emitting diodes emitlight individually; a light-receiving means for outputting a signalbased on photoelectromotive force of each of part of light-emittingdiodes among said plurality of light-emitting diodes; a scanning controlmeans for controlling said light-emitting means to make each of saidlight-emitting diodes emit light which is positioned neighboring saideach of part of light-emitting diodes that said light-receiving meansoutputs said signal based on the photoelectromotive force of, and forcontrolling said light-receiving means to output said signal in thelight-emitting state; a generating means for generating two-dimensionalresidual image data of said plurality of light-emitting diodes, based onthe signals which are outputted from said light-receiving means andwhich are based on the photoelectromotive force of said part oflight-emitting diodes; a storing means for storing said two-dimensionalresidual image data; and a light-emission control means for controllingsaid light-emitting means to make said plurality of light-emittingdiodes emit light based on said two-dimensional residual image datastored in said storing means, in accordance with swinging of saidhousing.
 9. A residual image display device, comprising: a substantiallybar-shaped housing; a plurality of light-emitting diodes arranged alonga longitudinal direction of said housing; a light-emitting means formaking each of said plurality of light-emitting diodes emit lightindividually; a light-receiving means for outputting a signal based onphotoelectromotive force of each of said plurality of light-emittingdiodes; a scanning control means for cotrolling said light-emittingmeans to make each of said light-emitting diodes emit light which ispositioned neighboring said each of light-emitting diodes that saidlight-receiving means outputs said signal based on thephotoelectromotive force of, and for controlling said light-receivingmeans to output said signal in the light-emitting state; a generatingmeans for generating two-dimensional residual image data of part oflight-emitting diodes among said plurality of light-emitting diodes,based on the signals which are outputted from said light-receiving meansand which are based on the photoelectromotive force of said plurality oflight-emitting diodes; a storing means for storing said two-dimensionalresidual image data; and a light-emission control means for controllingsaid light-emitting means to make said part of light-emitting diodesamong said plurality of light-emitting diodes emit light based on saidtwo-dimensional residual image data stored in said storing means, inaccordance with swinging of said housing.
 10. A residual image displaydevice, comprising: a substantially bar-shaped housing; a plurality oflight-emitting diodes arranged along a longitudinal direction of saidhousing; a light-emitting means for making said light-emitting diodesemit light individually; a light-receiving means for outputting a signalbased on photoelectromotive force of each of said light-emitting diodes;a scanning control means for controlling said light-emitting means tomake each of said light-emitting diodes emit light which is positionedneighboring said each of said light-emitting diodes that saidlight-receiving means outputs said signal based on thephotoelectromotive force of, and for controlling said light-receivingmeans to output said signal in the light-emitting state; a generatingmeans for generating two-dimensional residual image data used forlight-emission control of said light-emitting diodes, based on thesignals which are outputted from said light-receiving means and whichare based on the photoelectromotive force of said light-emitting diodes;a storing means for storing said two-dimensional residual image data;and a light-emission control means for controlling said light-emittingmeans to make said plurality of light-emitting diodes emit light basedon said two-dimensional residual image data stored in said storingmeans, in accordance with swinging of said housing, wherein saidlight-emission control means controls light emission so that alight-emission period of said light-emitting diodes based on saidtwo-dimensional residual image data is equal to or less than 1/30second.
 11. The residual image display device according to claim 8,further comprising a detecting means for detecting a change of a swingdirection of said housing, wherein, with using a timing when saiddetecting means detects the change of the swing direction as a standardtiming, after only a period from a finishing timing of lastlight-emission of said light-emitting diodes by said two-dimensionalresidual image data to said timing when said detecting means detects thechange of the swing direction is passed, said light-emission controlmeans starts light-emission of said light emitting diodes by saidtwo-dimensional residual image data.
 12. The residual image displaydevice according to claim 9, further comprising a detecting means fordetecting a change of a swing direction of said housing, wherein, withusing a timing when said detecting means detects the change of the swingdirection as a standard timing, after only a period from a finishingtiming of last light-emission of said light-emitting diodes by saidtwo-dimensional residual image data to said timing when said detectingmeans detects the change of the swing direction is passed, saidlight-emission control means starts light-emission of said lightemitting diodes by said two-dimensional residual image data.
 13. Theresidual image display device according to claim 10, further comprisinga detecting means for detecting a change of a swing direction of saidhousing, wherein, with using a timing when said detecting means detectsthe change of the swing direction as a standard timing, after only aperiod from a finishing timing of last light-emission of saidlight-emitting diodes by said two-dimensional residual image data tosaid timing when said detecting means detects the change of the swingdirection is passed, said light-emission control means startslight-emission of said light emitting diodes by said two-dimensionalresidual image data.
 14. A residual image display device, comprising: asubstantially bar-shaped housing; a plurality of light-emitting diodesarranged along a longitudinal direction of said housing; a plurality ofback face light-emitting diodes arranged along said longitudinaldirection of said housing, in a back face of said housing that is areverse-side of said plurality of light-emitting diodes; alight-emitting means for making said light-emitting diodes and said backface light-emitting diodes emit light individually; a light-receivingmeans for outputting a signal based on photoelectromotive force of eachof said plurality of light-emitting diodes; a scanning control means forcontrolling said light-emitting means to make each of saidlight-emitting diodes emit light which is positioned neighboring saideach of said light-emitting diodes that said light-receiving meansoutputs said signal based on the photoelectromotive force of, and forcontrolling said light-receiving means to output said signal in thelight-emitting state; a generating means for generating two-dimensionalresidual image data used for light-emission control of saidlight-emitting diodes, based on the signals which are outputted fromsaid light-receiving means and which are based on the photoelectromotiveforce of said light-emitting diodes; a storing means for storing saidtwo-dimensional residual image data; and a light-emission control meansfor controlling said light-emitting means to make said plurality oflight-emitting diodes and said back face light-emitting diodes emitlight based on said two-dimensional residual image data stored in saidstoring means, in accordance with swinging of said housing.
 15. Aresidual image display device, comprising: a substantially bar-shapedhousing; a plurality of light-emitting diodes arranged along alongitudinal direction of said housing; a plurality of different colorlight-emitting diodes emitting light of a color different from that ofsaid plurality of light-emitting diodes, being arranged correspondinglyto each of said plurality of light-emitting diodes; a light-emittingmeans for making said light-emitting diodes and said different colorlight-emitting diodes emit light individually; a light-receiving meansfor outputting a signal based on photoelectromotive force of each ofsaid light-emitting diodes; a scanning control means for controllingsaid light-emitting means to make each of said light-emitting diodesemit light which is positioned neighboring said each of saidlight-emitting diodes that said light-receiving means outputs saidsignal based on the photoelectromotive force of, and for controllingsaid light-receiving means to output said signal in the light-emittingstate; a generating means for generating two-dimensional residual imagedata used for light-emission control of said light-emitting diodes,based on the signals which are outputted from said light-receiving meansand which are based on the photoelectromotive force of saidlight-emitting diodes; a storing means for storing said two-dimensionalresidual image data; and a light-emission control means for controllingsaid light-emitting means to make said plurality of light-emittingdiodes emit light based on said two-dimensional residual image datastored in said storing means, and controlling said light-emitting meansto make said plurality of different color light-emitting diodescorresponding to each of said light-emitting means which dose not emitlight, in accordance with swinging of said housing.
 16. The residualimage display device according to claim 15, wherein said scanningcontrol means controlling, instead of to make each of saidlight-emitting diodes emit light which is positioned neighboring saideach of said light-emitting diodes to perform scanning, to make each ofsaid different color light-emitting diodes emit light which ispositioned neighboring said each of said light-emitting diodes toperform scanning, and for controlling to make said each oflight-emitting diodes receive reflected light of said light.